This invention relates to surgical equipment, and more particularly to equipment used to clamp blood vessels. Even more particularly, the invention relates to hemostatic clips used to ligate or clamp blood vessels during surgical procedures.
Hemostatic clips have been used in surgery for over 60 years. They were designed to perform two basic functions--ligation of a vessel, nerve, or fluid duct in the human body; or marking a specific surgical site, typically the periphery of a tumor, which will later show up on an X-ray. The clips are permanently implanted in the body and are radiopaque. Originally hemostatic clips were formed in a "V" shape. However, when this shape is closed, it tends to push the vessel away from the clip or cut the vessel rather than clamp it. This problem was solved by a preformed hemostatic clip which resembles the shape of a horseshoe, described in U.S. Pat. Nos. 3,323,216 and 3,363,628, which is now commonly used. The horseshoe clip has two essentially parallel legs which cause an initial distal tip to tip closing action that contains the vessel within the clip to fully control the vessel before ligation.
Occasionally the clip of U.S. Pat. No. 3,363,628 will sever a vessel or the clip will slip from the point of application. As will be described below, if the prior art clips are applied with a misaligned applier, no space will be left between the arms of the clip for the walls of the vessel, and the vessel will be crushed. An inadequate vessel wall surface contact area may also cause the clip to slip from its point of application.
This problem is well known in the art, and others have attempted to solve it. For example, U.S. Pat. No. 4,188,953 issued Feb. 19, 1980 to Klieman, et al. placed diagonal recesses in the two arms. U.S. Pat. No. 4,844,066 issued July 4, 1989 to Stein left an ungrooved area at the tip of the clip.
The manufacturing process for prior art clips often leaves rough surfaces on the clip and may leave "sharks teeth" where the lateral serrations were stamped. These may gouge the vessel when the clip is applied.
It is thus apparent that there is a need in the art for an improved hemostatic clip that will leave space for the vessel walls, even if applied by a misaligned applier. There is a further need for a clip with a large, smooth surface area free from sharp edges and protrusions. The present invention meets these needs.